Here's why:

* The sun is a star: It produces its own light and heat through nuclear fusion.

* The moon reflects sunlight: The moon doesn't produce light, it simply reflects the light from the sun.

Even though the sun appears much smaller than the moon in the sky, it's vastly more powerful. The sun is about 400 times farther away from Earth than the moon, but it's also about 400,000 times brighter!